Coffee filter



Aug. 3, 1948.

COFFEE FILTER Fild May 18, 1945' n I ""6 w m? 9 I, r L a e w \m .0 3i mma m N M n. w W

Patented Aug. 3, 1948 UNITED: STATES @F 'F [C E 2,446,499. COFFEEFILTER;

I Donald E. Van Denberg, Rockford; Ill.

ApplicatiomMayJS, 1945; Serial No: 594 458 This invention relates tostrainers for glass infusion coffee brewers and the like.

Among other objects, the invention aims toprovide a wire cloth strainerof improved efficiency and durability.

Another object is to provide an improved and adjustable means forremovably holding the strainer in place.

Other objects and advantages will become apparent from the followingdescription of one device embodying the invention and shown in theaccompanying drawing.

In said drawing:

Figure 1 is a perspective view of the strainer element in position in acoffee brewer and illustrating its connection thereto.

Fig. 2 is a bottom view of the strainer, omitting the connecting means.

Fig. 3 is a vertical section of the strainer.

Fig. 4 is a plan view of a holding element.

Fig. 5 is an enlarged fragmentary section of certain parts shown in Fig.3.

In coffee brewers of the type here involved straining of the coffee,that is, separation of the liquid from the coffee grounds is generallyaided by the partial vacuum produced upon condensation of the steaminside of the sealed pot 9. However, often this vacuum is lost byleakage at the seal, whereupon filtering through the ordinary filteringdevice is objectionably slow. To compensate therefor, the filteringdevices are made courser to hasten filtering with consequent reductionin clarity and quality of the coffee brew. Attempts have been made toimprove clarity by the use of large-area semispherical screens, but ithas not heretofore been possible to fabricate a durable and efficientscreen of this character. The screen must necessarily be of very finemesh wire cloth which alone is relatively fiimsy and incapable ofmaintaining its shape.

According to my invention, I employ a straining element in the form of afine mesh wire cloth is shaped to general semispherical form which issupported and reinforced in such a way as to render it durable and tomaintain its efficiency through long periods of use. The strainer clothis supported and reinforced adjacent its free edge by an annulus in theform of a stifi metal ring 42 engaging the upwardly extending lowermargin it of the strainer thereby tending to stiffen and support thearch M of the strainer. The latter is thus able to present a largefiltering surface which does not readily clog. Ring 12 is provided withsome means by which the strainer may be anchored in place. Any suitablemeans such 1 Claim. (01. 2107-162) may=:besemployedpforgthiszpurposeiAneintfigrfil. loop l5 (formed by striking dowmaloonofmetall;providessaz, connection; byywhichi' the strainer is remova'bly anchoredin place as presently described.

Ring IB is provided with a laterally extending flange E6 to form thestrainer bearing surface with the brewer. Cooperating with thesupporting ring i2 is an outer ring ll shaped to the outer contour ofthe strainer opposite ring l2, between which and ring l2 the margin l3of the screen is firmly held to aid in effecting the stiffening andsupporting of the strainer arch as above described. Ring H is preferablypro-vided with a laterally extending flange I8 around which the outermargin of flange [6 is crimped and by which ring H and flange l2 areheld in firm clamping relation over the strainer margin l3 (see Fig. 5).If desired, the screen margin may additionally be soldered to ring I2.

The lower surface of flange I6 is flat and seats against the surface [9of the brewer around the infusion tube 20. The multiple thicknesses ofmetal embraced within the crim-ped over flange l6 stiflens the latterand prevents distortion which would permit escape of coffee groundsbetween the strainer and the surface IQ of the brewer.

The strainer is removably held in seated position by an adjustableholder 2| (in the form of a bar narrower than the internal diameter ofthe tube) which equally bears against opposite regions of the end 32 ofthe tube and which is connected to the strainer by a flexible andresilient connector. The latter is in the form of a so-called shot chain33 and a tension spring 5'34 connecting the chain to the strainer. Oneend of the spring is hooked to the connection 15 and the other is bentsnugly around the chain between a pair of shot. The bar 2! is providedwith a bayonet slot 35 to receive the chain 33 and by which the springtension and effective length of the connector may be adjusted to tubesof varying lengths. To release the connector the spring is elongated bypulling down the free end 36 of the chain until the bar 2! can be tiltedand inserted endwise in the tube 29.

Obviously, the invention is not limited to the details of theillustrative apparatus since these may be variously modified. Moreover,it is not indispensable that all features of the invention be usedconjointly, since various features may be used to advantage in differentcombinations and subcombinations.

I claim as my invention:

A strainer for a vacuum type coffee brewer having an infusion tubecomprising in combination a strainer adapted to seat in the entranc endof said tube, a flexible connection longer than said tube attached atone end to the underside of said strainer for holding the strainerseated in said entrance end, said connection including a resilientlyextensible portion adjacent the strainer and a lower end portion havinga multiplicity of enlargements interconnected with each other and spacedlongitudinally along the flexible connection and a cross-bar longer thanthe diameter of said tube and apertured intermediate its ends to providea recess permitting the passage of said enlargements therethrough, andan adjoining slot narrower than the diameter of said enlargements butloosely receiving any part of said connection intervening between saidenlargements whereby to permit tilting of the cross-bar to a positionalongside said connection and thereby allow withdrawal of the connectionendwise through said tube.

DONALD E. VAN DENBERG.

REFERENCES CITED The following references are of record in the file ofthis patent:

